1. Field
The present invention generally relates to the field of image processing. Particularly, the invention relates to a method and apparatus for removing a mark in a document image effectively and accurately.
2. Description of the Related Art
In recent years, the technologies related to scanners have been developed rapidly. For example, those skilled in the art have made their great efforts to improve the processing effects of background perspective detection and removal, a document layout analysis, optical character recognition, and other technical aspects of a scanned document image. However, only the improvements in these aspects may not be sufficient, to achieve a better technical effect as a whole, all the aspects in the related art need to be improved.
For example, there are frequently a variety of marks in the scanned document image, e.g., a watermark to show the origin or ownership of the scanned document image, and a copymark to avoid a copy from being illegally used. These marks appearing as serious background noise may make it much more difficult to perform optical character recognition, and other processing. Moreover, these marks may seriously degrade the reading experience of a reader. FIG. 1 illustrates an example of the scanned document image with the watermark, and FIG. 2 illustrates an example of the scanned document image with the copymark.
Conventionally, a mark is removed typically through processing the document image on a pixel basis. Apparently, only the pixel level information is used in processing the document image on a pixel basis, so the limited information may make such processing relatively difficult and consequently a result of processing relatively inaccurate.
In view of this, there is a need of a method and apparatus capable of removing a mark in a document image effectively and accurately.